scholarly journals Study of tropospheric scintillation effects in Ku-band frequency for satellite communication system

2020 ◽  
Vol 10 (3) ◽  
pp. 3136
Author(s):  
Nadirah Abdul Rahim ◽  
Hanis Nabilah A. Mulop ◽  
Khairayu Badron
Keyword(s):  
Electromagnetic Waves ◽  
Satellite Communication ◽  
Elevation Angle ◽  
Small Scale ◽  
Band Frequency ◽  
Clear Sky ◽  
Tropospheric Scintillation ◽  
Sky Conditions ◽  
Beacon Signal ◽  
Ku Band

Scintillation is a rapid fluctuation of an electromagnetic waves in terms of phase and amplitude due to a small-scale inconsistency in the transmission path (or paths) with time. Scintillation exists continuously throughout a day whether during raining or clear sky conditions. The raw signal data need to exclude other propagations factors that include signal fluctuations to further understand the scintillation studies. This paper presents the analysis of tropospheric scintillation data from January 2016 till December 2016 at Ku-band frequency of 12.202 GHz beacon signal. The experimental data from MEASAT 3B were collected and analyzed to see the effect of tropospheric scintillation. The elevation angle of the dish antenna is 77.45o. The highlighted objectives are to analyze the scintillation data at Ku-band, and to compare and validate the results with other scintillation models. The result shows that the stipulated scintillation analysis has higher amplitude, which is 0.73 dB compared to other scintillation analysis which has lower scintillation amplitude: 0.45 dB (Karasawa), 0.42 dB (ITU-R), 0.4 dB (Nadirah & Rafiqul), 0.42 dB (Van De Kamp) and 0.11 dB (Anthony & Mandeep).

Seasonal and Diurnal Variation on Tropospheric Scintillation at Ku-Band in Tropical Climate

2016 ◽  
Vol 6 (4) ◽  
pp. 1710
Author(s):  
Ibtihal Fawzi Elshami ◽  
Jafri Din
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Elevation Angle ◽  
Signal Amplitude ◽  
Clear Sky ◽  
South West Monsoon ◽  
One Year ◽  
Tropospheric Scintillation ◽  
Propagation Measurement ◽  
Ku Band

Tropospheric scintillation is a rapid fluctuation of the received signal amplitude which can cause propagation impairments that affect satellite communication systems operating above 10 GHz. Scintillation data was collected in Equatorial Johor Bahru, Malaysia, based on a one-year Ku-band propagation measurement campaign, utilizing MEASAT-1 Satellite with an antenna elevation angle of 75.61°. This work concentrates on the probability density function (PDF) of diurnal variations of clear sky scintillation variance analyzed on an hourly basis. Besides, seasonal variation of scintillation amplitude has been presented in this paper. From the results, it is concluded that clear sky scintillation variance is likely to occur during morning and afternoon periods. Moreover, clear sky scintillation amplitude of the South-West monsoon shows a relatively higher comparing with others monsoon seasons. Hence, signal attenuation based on seasonal and diurnal information is of great interest for the system designers to appropriately design fade margin.Tropospheric scintillation is a rapid fluctuation of the received signal amplitude which can cause propagation impairments that affect satellite communication systems operating above 10 GHz. Scintillation data was collected in Equatorial Johor Bahru, Malaysia, based on a one-year Ku-band propagation measurement campaign, utilizing MEASAT-1 Satellite with an antenna elevation angle of 75.61°. This work concentrates on the probability density function (PDF) of diurnal variations of clear sky scintillation variance analyzed on an hourly basis. Besides, seasonal variation of scintillation amplitude has been presented in this paper. From the results, it is concluded that clear sky scintillation variance is likely to occur during morning and afternoon periods. Moreover, clear sky scintillation amplitude of the South-West monsoon shows a relatively higher comparing with others monsoon seasons. Hence, signal attenuation based on seasonal and diurnal information is of great interest for the system designers to appropriately design fade margin.

scholarly journals Seasonal and Diurnal Variation on Tropospheric Scintillation at Ku-Band in Tropical Climate

2016 ◽  
Vol 6 (4) ◽  
pp. 1710
Author(s):  
Ibtihal Fawzi Elshami ◽  
Jafri Din
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Elevation Angle ◽  
Signal Amplitude ◽  
Clear Sky ◽  
South West Monsoon ◽  
One Year ◽  
Tropospheric Scintillation ◽  
Propagation Measurement ◽  
Ku Band

Tropospheric scintillation is a rapid fluctuation of the received signal amplitude which can cause propagation impairments that affect satellite communication systems operating above 10 GHz. Scintillation data was collected in Equatorial Johor Bahru, Malaysia, based on a one-year Ku-band propagation measurement campaign, utilizing MEASAT-1 Satellite with an antenna elevation angle of 75.61°. This work concentrates on the probability density function (PDF) of diurnal variations of clear sky scintillation variance analyzed on an hourly basis. Besides, seasonal variation of scintillation amplitude has been presented in this paper. From the results, it is concluded that clear sky scintillation variance is likely to occur during morning and afternoon periods. Moreover, clear sky scintillation amplitude of the South-West monsoon shows a relatively higher comparing with others monsoon seasons. Hence, signal attenuation based on seasonal and diurnal information is of great interest for the system designers to appropriately design fade margin.Tropospheric scintillation is a rapid fluctuation of the received signal amplitude which can cause propagation impairments that affect satellite communication systems operating above 10 GHz. Scintillation data was collected in Equatorial Johor Bahru, Malaysia, based on a one-year Ku-band propagation measurement campaign, utilizing MEASAT-1 Satellite with an antenna elevation angle of 75.61°. This work concentrates on the probability density function (PDF) of diurnal variations of clear sky scintillation variance analyzed on an hourly basis. Besides, seasonal variation of scintillation amplitude has been presented in this paper. From the results, it is concluded that clear sky scintillation variance is likely to occur during morning and afternoon periods. Moreover, clear sky scintillation amplitude of the South-West monsoon shows a relatively higher comparing with others monsoon seasons. Hence, signal attenuation based on seasonal and diurnal information is of great interest for the system designers to appropriately design fade margin.

scholarly journals Preparation and Characterization of CuFe2O4 Nanoparticles by the Sol-Gel Method and Investigation of Its Microwave Absorption Properties at Ku-Band Frequency Using Silicone Rubber

Proceedings ◽  
2018 ◽  
Vol 2 (17) ◽  
pp. 1155 ◽  
Author(s):  
Reza Peymanfar ◽  
Farzaneh Azadi ◽  
Yousef Yassi
Keyword(s):  
Microwave Absorption ◽  
Silicone Rubber ◽  
Electromagnetic Waves ◽  
Sol Gel ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Band Frequency ◽  
Gel Method ◽  
Sol Gel Method ◽  
Ku Band

Recently, using microwave devices that emit electromagnetic waves and enhance the convenience of life have increased; however, they can be harmful to the environment. In this study, CuFe2O4 nanoparticles were prepared through the conventional sol-gel procedure and then were characterized by X-ray powder diffraction (XRD), vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), and vector network analyzer (VNA) using S parameters. Results illustrated that pure crystal structure of magnetic nanoparticles has been synthesized by the sol-gel method with magnetic saturation (Ms) of 22 emu/g. Finally, CuFe2O4 nanoparticles were composited by silicone rubber to investigate its microwave absorption properties. Results showed that the CuFe2O4/silicone rubber nanocomposite absorbed more than 94.87% of the microwave irradiation at ku-band frequency with 1.7 mm thickness and the maximum reflection loss was −60.38 dB at 16.1 GHz. Magnetic and dielectric properties of the CuFe2O4 nanoparticles and silicone rubber polymeric matrix in the nanocomposite demonstrated desirable microwave absorption properties.

CLEAR SKY DIURNAL BEHAVIOR OF TROPOSPHERIC SCINTILLATION AT KU-BAND SATELLITE COMMUNICATION IN EQUATORIAL MALAYSIA

2015 ◽  
Vol 77 (10) ◽  
Author(s):  
Ibtihal F. El-Shami ◽  
Hong Yin Lam ◽  
Jafri Din ◽  
Siat Ling Jong
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Prediction Models ◽  
Elevation Angle ◽  
Signal Amplitude ◽  
Radio Communication ◽  
Significant Discrepancy ◽  
Comparison Results ◽  
Diurnal Behavior ◽  
Tropospheric Scintillation

Tropospheric scintillation is referred to rapid fluctuation of received signal amplitude. It can cause propagation impairments that affect satellite communication systems operating at above 10 GHz of frequency. In this work, we have exploited 1 year of measured broadcasting signal data collected in Johor, Malaysia to investigate the effects of scintillation intensity on a SatCom system operating at 11.075 GHz with its links pointed towards the MEASAT-1 satellite (an elevation angle of 75.61°). We have investigated the behavior of this scintillation amplitude through the classification and analysis of a time-series satellite broadcasting signal and have then compared the statistical results with existing scintillation prediction models. The comparison results indicate that there is a significant discrepancy between measured data and those models and that the performance of these prediction models does not appear to be satisfactory, with the exception of the ITU-R and the Ortgies Refractivity model. In addition, we have investigated the diurnal behavior of the scintillation intensity at four different periods of the day and proposed a modified Marzano model to accommodate local meteorological input parameters. The models performances are assessed against the available measurement dataset. The proposed models provide system operators and radio communication engineers with critical information on the fluctuations of tropospheric scintillation variance on the satellite signal during a typical day taken into the account of local meteorological peculiarities.

scholarly journals Experimental analysis and comparison of tropospheric scintillation prediction models using eutelsat-36b satellite in a tropical Nigeria

2017 ◽  
Vol 7 (1) ◽  
pp. 8 ◽  
Author(s):  
Joseph Ojo ◽  
Babatunde Rabiu ◽  
Sandro Radicella ◽  
Obisesan Obiyemi
Keyword(s):  
Communication Systems ◽  
Prediction Models ◽  
Model Performance ◽  
Systems Design ◽  
Percentage Error ◽  
Seasonal Effect ◽  
Band Frequency ◽  
Average Bit Error Probability ◽  
Tropospheric Scintillation ◽  
Ku Band

Knowledge on clear-air effects is of paramount importance to proper link budgeting for optimum communication systems design performances. In this paper, one-year (January - December 2013) tropospheric scintillation data are extracted from the EUTELSAT-36B Ku-band satellite measurements installed at Akure (Lat: 7.17 oN, Long: 5.18 oE, Alt: 358 m) for statistical analysis and the result compared with some established troposphere scintillation models in order to obtain the best prediction model performance for this region. The result shows that even in the absence of rain, tropospheric scintillation shows a strong seasonal effect in this region up to amplitude above 0.92 dB. The scintillation intensity fits better to gamma distribution at a high scintillation level taken into consideration the local meteorological parameters. Models comparison with experimental data also shows that the Karasawa model with the lowest percentage error of about 7% was found to be best fit for predicting propagation impairment relating to be fading at a Ku band frequency in this region. The overall results will provide information on scintillation margin needed for sizing antennas and amplifiers for reliable performance and the average bit-error probability on a scintillation-degraded digital satellite link in this region.

scholarly journals Generation of Beam Tilt through Three-Dimensional Printed Surface

Electronics ◽  
2021 ◽  
Vol 10 (24) ◽  
pp. 3174
Author(s):  
Sujan Shrestha ◽  
Hijab Zahra ◽  
Syed Muzahir Abbas ◽  
Arslan Kiyani ◽  
Bahare Mohamadzade ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Low Cost ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Operating Frequency Range ◽  
Input Source ◽  
3D Printed ◽  
Ku Band

In this paper, 3D printed surfaces are presented to study this technology’s application in generating beam tilt for the electromagnetic waves in the Ku-band. Additionally, the input source is maintained by a feed horn that is additively manufactured and is coated with copper spray paint to add conductivity, which is fed by a WR-75 waveguide. The proposed beam tilt generating surface is also referred to as a Beam Deviating Surface (BDS). There is no relative gap between the BDS and the aperture of the horn, which eventually decreased the overall antenna height. The BDS layer is able to deviate the beam for a fixed elevation angle of 22.5∘ and could be consequently rotated along with the rotation of the BDS prototype. The voltage standing wave ratio value is less than two over the operating frequency range, which depicts the wideband behavior. The measured and simulated radiation patterns show that we can tilt the electromagnetic waves in ranges of up to +/−22.5∘ with a minimum side lobe level of −5 dB at frequencies from 10 to 15 GHz. This signifies the wideband characteristic of the proposed prototype, which is achieved by Vero material from Multijet Printing that is a low-cost and rapid manufacturing 3D printing technology.

scholarly journals Modification of ITU-R Parameters to Improve the Prediction of Tropospheric Scintillation for Tropical Regions

2018 ◽  
Vol 7 (3.12) ◽  
pp. 1078 ◽  
Author(s):  
John Philip B ◽  
Sarat K Kotamraju ◽  
Ch Sri Kavya
Keyword(s):  
Prediction Model ◽  
Satellite Communication ◽  
Tropical Region ◽  
Communication Link ◽  
Efficient System ◽  
Tropical Regions ◽  
Signal Degradation ◽  
Tropospheric Scintillation ◽  
Beacon Signal ◽  
Rapid Fluctuation

Scintillation is the rapid fluctuation of the received signal. It is caused by the variation in the refractivity structure of the atmosphere profile. This phenomenon leads to the signal degradation and is significant in low fade margin links and at low elevation angles. So, analyzing the scintillation intensity and its statistics are vital for a system designer to design an efficient system for the satellite communication link. This paper presents the methodology to extract the scintillation intensity from the raw beacon signal and comparison of ITU-R scintillation prediction model with the measured results to test its acceptability over tropical region. When compared with measured results, ITU-R model overestimates the scintillation fade. Hence the parameters of the time percentage factor are modified to obtain near fit to the measured results.

scholarly journals Characterization of concurrent ku band tropospheric scintillation and rain attenuation in Malaysia

2019 ◽  
Vol 15 (2) ◽  
pp. 956
Author(s):  
Ibtihal Fawzi Elshami ◽  
Jafri Din ◽  
Lam Hong Yin ◽  
Ali I Elgayar
Keyword(s):  
Communication Systems ◽  
Satellite Communication ◽  
Power Spectral Analysis ◽  
Rain Attenuation ◽  
Significant Information ◽  
Tropical Regions ◽  
Significant Impairment ◽  
One Year ◽  
Tropospheric Scintillation ◽  
Ku Band

<span>Tropospheric scintillation in satellite communication systems operating at frequencies over 10 GHz is a significant impairment, especially in tropical regions, as attenuation affects scintillation dramatically. This work concentrates on tropospheric scintillation in equatorial Johor Bahru, Malaysia, based on a one-year Ku-band propagation measurement study utilising a direct broadcast receiver and an automatic weather station. This study aimed to investigate the relationship between wet scintillation and rain attenuation using experimental measurements. The power spectral analysis has been carried out to determine required cut-off frequency of filtering to separate out rain attenuation and scintillation effects. The results can provide significant information on the fluctuations of wet scintillation at Ku-band earth space link in tropical regions.</span>

Evaluation of net shortwave radiation over China with a regional climate model

2020 ◽  
Vol 80 (2) ◽  
pp. 147-163
Author(s):  
X Liu ◽  
Y Kang ◽  
Q Liu ◽  
Z Guo ◽  
Y Chen ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Radiant Energy ◽  
Energy System ◽  
Radiation Budget ◽  
Shortwave Radiation ◽  
Monsoon Region ◽  
Clear Sky ◽  
Sky Conditions

The regional climate model RegCM version 4.6, developed by the European Centre for Medium-Range Weather Forecasts Reanalysis, was used to simulate the radiation budget over China. Clouds and the Earth’s Radiant Energy System (CERES) satellite data were utilized to evaluate the simulation results based on 4 radiative components: net shortwave (NSW) radiation at the surface of the earth and top of the atmosphere (TOA) under all-sky and clear-sky conditions. The performance of the model for low-value areas of NSW was superior to that for high-value areas. NSW at the surface and TOA under all-sky conditions was significantly underestimated; the spatial distribution of the bias was negative in the north and positive in the south, bounded by 25°N for the annual and seasonal averaged difference maps. Compared with the all-sky condition, the simulation effect under clear-sky conditions was significantly better, which indicates that the cloud fraction is the key factor affecting the accuracy of the simulation. In particular, the bias of the TOA NSW under the clear-sky condition was <±10 W m-2 in the eastern areas. The performance of the model was better over the eastern monsoon region in winter and autumn for surface NSW under clear-sky conditions, which may be related to different levels of air pollution during each season. Among the 3 areas, the regional average biases overall were largest (negative) over the Qinghai-Tibet alpine region and smallest over the eastern monsoon region.

Efficient downscaling of satellite oceanographic data with convolutional neural networks

2021 ◽  
Vol 12 (3) ◽  
pp. 46-47
Author(s):  
Nikita Saxena
Keyword(s):  
Neural Networks ◽  
Deep Learning ◽  
Convolutional Neural Networks ◽  
Super Resolution ◽  
Sea Surface ◽  
Clear Sky ◽  
Oceanographic Data ◽  
Computationally Expensive ◽  
Sky Conditions ◽  
Data Inference

Space-borne satellite radiometers measure Sea Surface Temperature (SST), which is pivotal to studies of air-sea interactions and ocean features. Under clear sky conditions, high resolution measurements are obtainable. But under cloudy conditions, data analysis is constrained to the available low resolution measurements. We assess the efficiency of Deep Learning (DL) architectures, particularly Convolutional Neural Networks (CNN) to downscale oceanographic data from low spatial resolution (SR) to high SR. With a focus on SST Fields of Bay of Bengal, this study proves that Very Deep Super Resolution CNN can successfully reconstruct SST observations from 15 km SR to 5km SR, and 5km SR to 1km SR. This outcome calls attention to the significance of DL models explicitly trained for the reconstruction of high SR SST fields by using low SR data. Inference on DL models can act as a substitute to the existing computationally expensive downscaling technique: Dynamical Downsampling. The complete code is available on this Github Repository.

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